Re: [PATCH 5/7] x86,tlb: only send page table free TLB flush to lazy TLB CPUs

[Mike Galbraith]

(bah, I see I replied to wrong patch version, but it's still valid)

On Sat, 2018-07-07 at 14:26 +0200, Mike Galbraith wrote:
> On Fri, 2018-06-29 at 10:29 -0400, Rik van Riel wrote:
> > diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
> > index e59214ec52b1..c4073367219d 100644
> > --- a/arch/x86/mm/tlb.c
> > +++ b/arch/x86/mm/tlb.c
> > @@ -718,14 +718,47 @@ void tlb_flush_remove_tables_local(void *arg)
> >  	}
> >  }
> >  
> > +static void mm_fill_lazy_tlb_cpu_mask(struct mm_struct *mm,
> > +				      struct cpumask* lazy_cpus)
> > +{
> > +	int cpu;
> > +
> > +	for_each_cpu(cpu, mm_cpumask(mm)) {
> > +		if (!per_cpu(cpu_tlbstate.is_lazy, cpu))
> > +			cpumask_set_cpu(cpu, lazy_cpus);
> > +	}
> > +}
> > +
> >  void tlb_flush_remove_tables(struct mm_struct *mm)
> >  {
> >  	int cpu = get_cpu();
> > +	cpumask_var_t lazy_cpus;
> > +
> > +	if (cpumask_any_but(mm_cpumask(mm), cpu) >= nr_cpu_ids)
> > +		return;
> 
> A put_cpu() went missing.
> 
> > +
> > +	if (!zalloc_cpumask_var(&lazy_cpus, GFP_ATOMIC)) {
> > +		/*
> > +		 * If the cpumask allocation fails, do a brute force flush
> > +		 * on all the CPUs that have this mm loaded.
> > +		 */
> > +		smp_call_function_many(mm_cpumask(mm),
> > +				tlb_flush_remove_tables_local, (void *)mm, 1);
> > +		return;
> > +	}
> 
> Ditto.
> 
> 	-Mike